1. Field of the Invention
This invention relates to a packing bag and manufacturing method for the packing bag.
2. Description of the Related Art
Conventionally, the applicant of the present application has proposed a packing bag formed by welding a sheet material of synthetic resin to tightly seal and preserve stored articles with sanitation (refer to Japanese Patent No. 5715283).
In the packing bag disclosed by Japanese Patent No. 5715283, as shown in FIG. 32, a heated blade contacts a face 40a of a sheet material 40 to form a half-cut V-shaped groove 48, and a separation-prepared line portion 49 to be separated by human hands is formed with the V-shaped groove 48.
However, in a case that the sheet material 40 has welding resin layers 46A and 46B on both sides 40a and 40b, and a barrier layer 47 in the middle, the V-shaped groove 48 penetrates (breaks) the barrier layer 47 and barrier function is greatly reduced.
And, when the depth of the V-shaped groove 48 does not reach for the barrier layer 47, separation of the separation-prepared line portion 49 is difficult.
Therefore, it is an object of the present invention to provide a packing bag and manufacturing method for the packing bag with which the separation-prepared line portion can be smoothly separated, and the barrier function can be certainly kept.